<!DOCTYPE html>
<html>
<head>
    <title>点击按钮时加载内嵌页面</title>
    <style>
    .progressbar {
  border: 1px solid #CCC;
  height: 20px;
  width: 200px;
  border-radius: 10px;
  overflow: hidden;
}

.progress {
  background: green;
  height: 100%;
  color: white;
  text-align: center;
  transition: width 0.5s ease;
}

    </style>
</head>
<body>
<div class="progressbar">
  <div class="progress" style="width: 70%;">70%</div>
</div>

</body>
</html>
